1. Field of the Invention
The present invention relates to storage apparatus and a data management method employing this storage apparatus, and particularly relates to technology for controlling power saving of a disk device.
2. Description of Related Art
The amount of data processed by computer systems is increasing evermore in accompaniment with the advancement of hardware technology. This storage apparatus is the core of a computer system managing vast amounts of data.
During the installation and operation of storage apparatus, there is typically a demand to keep data maintenance management costs down. Data maintenance management costs typically include cost (i.e., bit cost) per bit and power consumption costs in operation.
Technology combining disk devices having distinct performance in order to reduce bit cost while fulfilling the specifications demanded of storage apparatus is well known. For example, as shown in patent document 1 described below, it is known in the art as a storage apparatus that large capacity low-cost SATA disk devices and high-reliability high cost FC disk devices are combined in a hierarchical manner. High priority data is then stored in FC disk devices, whereas data of a comparatively low priority is stored in SATA disk devices.
In addition, technology for stopping disk devices for which data access has not taken place for a long time in order to reduce power consumption costs in operation is well-known. For example, patent document 2 discloses a storage apparatus that suppress power consumption by limiting operation of disk devices according to the frequency of receiving I/O commands sent from the host apparatus and stopping disk devices of low frequency.
[Patent Document 1] Japanese Patent Laid-open Publication No. 2004-348876.
[Patent Document 2] Japanese Patent Laid-open Publication No. 2000-293314.